Growth and nutrient uptake of Gracilaria lemaneiformis under different nutrient conditions with implications for ecosystem services: A case study in the laboratory and in an enclosed mariculture area in the East China Sea.

Graphical abstract Highlights • Gracilaria lemaneiformis grew well under different nutrient conditions. • Gracilaria lemaneiformis had high nutrient removal efficiencies under different nutrient conditions. • Gracilaria lemaneiformis showed high ecosystem services in mariculture areas. Abstract The growth and nutrient uptake of Gracilaria lemaneiformis under different nutrient conditions, with implications for ecosystem services, were evaluated in the laboratory and in an enclosed mariculture sea area in Yantian Bay at the coast of East China Sea. In laboratory experiments, the specific growth rate (SGR) ranged 1.29%/d–7.99%/d, and nitrogen (N), phosphorus (P), and dissolved inorganic carbon (C) uptake rate was 0.067–1.603 μmol/(g∙h), 0.002–0.069 μmol/(g∙h), and 4.01–31.25 μmol/(g∙h), respectively, under different nutrient conditions. In field experiments, the SGR ranged from 6.30%/d to 13.00%/d, and the average C sequestration rate was 9.25 mg/(g DW·h) and 6.68 mg/(g DW·h) in the G. lemaneiformis cultivation area (region 1) and fish cage area (region 4), respectively. The NH 4 +-N uptake rate of G. lemaneiformis was the highest in region 1 and region 4 with 56.98 ± 4.81 μg/(g DW·h) and 38.68 ± 7.12 μg/(g DW·h), respectively. The maximum removal efficiency of NH 4 +-N, NO 3 −-N, NO 2 --N, and PO 4 3--P were 45.99–59.79%, 13.10–30.21%, 12.88–14.11%, and 27.07–31.49% in G. lemaneiformis cultivated areas compared with those in fish cage area. The extrapolated results showed that 1192.03 tonnes of C, 128.10 tonnes of N and 15.89 tonnes of P would be simultaneously sequestered from the seawater through G. lemaneiformis cultivation in Yantian Bay. Results indicated that G. lemaneiformis had high growth rates and nutrient removal efficiencies under different nutrient conditions, which made it a good candidate for seaweed/animals integrated multi-trophic aquaculture in nutrient bioextraction and economic diversification. [ABSTRACT FROM AUTHOR]